Are you constantly getting disconnected from the server when you turn in a quest in world of warcraft? I was having this problem also and it was driving me nuts for months. Months! I finally figured it out. I guess there are a number of potential solutions but they all seem to boil down to issues with the drivers for your ethernet controller. No other game has these issues (and I play a lot of different online games – UT2k4, Battlefield 2, a variety of Halflife 2 mods, to name just a few) so I blame blizzard, especially since the issue was introduced by them in a patch. Anyway, if you’re trying to fix it, first of all, use the Blizzard forums and search on things like ‘quest disconnect’ and ‘ethernet drivers.’ Since there are over 100 bajillion posts in there, it can be hard to find the solution. Helpful Blizzard even has a FAQ page for this issue, except it sucks and didn’t have the solution for me. If you can’t find something useful in their forums, and their FAQ page doesn’t solve it for you, and you have an nforce 4-based motherboard like me, try this (taken from a post in the blizzard forums by Tweedledree):

For network cards that support “Checksum Offloading”: Such as; Intel Pro 100 series, Marvell Yukon, Broadcom, 3com CNet, and Nvidia nForce, you may need to disable it to resolve this issue.

1. Goto “Start” > “Control Panel”. 2. Double click to open “Network Connections”. 3. Right click on your network adapter and go to properties. 4. Click on “Configure” and go to the “Advanced” tab. 5. Select “Checksum Offload” and choose disable in the window to the right. 6. Click on Ok

This worked for me and finally solved the constant disconnect problem I had been having.